The International Standard Book Number system is designed to help the bookselling industry control stock. In the UK, it’s also used as the basis of the Public Lending Right systems which pays authors a small amount each time their book is borrowed.
Do I have to have an ISBN?
No. There is no legal requirement to have one for your book, but you will need one if you want to sell through bookstores. The ISBN is attached to the format of the book, not the content, so hardback and paperback editions need different ISBNs.
Do I need an ISBN for my ebook?
According to the way the ISBN system works, you should need two: one for the Kindle version and one for the epub. However, at the moment, it’s not really worth getting one for a Kindle ebook if you’re only selling through Amazon because Amazon uses their own numbering system. An ISBN is more useful for an epub ebook as you may be selling through outlets that require one. Check the individual retailers’ and distributors’ requirements to see whether you need one or not. You may find the distributor will add one for you.
ISBNs for ebooks will become more important as the PLR system expands to include ebook lending. It’s worth checking the current situation on the PLR website.
How do I buy ISBNs?
Every country has its own ISBN system. In the UK, you buy them from Nielsen. In the US, you buy them from Bowker. The more you buy the cheaper they are.
The company producing my book are willing to provide an ISBN. Is that a good idea?
That depends on the deal they are offering. If you use another company’s ISBN, they are the publisher of record and, if you decide to switch companies later, you can’t take the ISBN with you. For example, if you publish a print edition with Createspace using a Createspace ISBN, you’ll need a different ISBN if you decide to do a proper print run with someone else or switch print-on-demand supplier, and you’ll have to leave your Smashwords ISBN behind if you decide to switch to a different distributor.
One reason it might pay to use a Createspace ISBN is if you want to sell into US libraries. You can only use Createspace’s extended distribution system to do that if you have one of their ISBNs because US libraries require the publisher to have a Library of Congress number.
I’m having some copies of my book produced by a different printer. Do I need a new ISBN?
Changing the printer while keeping everything else the same shouldn’t require a new ISBN provide it belongs to you.
I’m changing the cover. Do I need a new ISBN?
No, provided the book will still be the same size and layout.
I want to reprint my book with a larger font on larger pages? Do I need a new ISBN?
Yes, because you’re changing the format of the book.
I bought some ISBNs under my own name but now I’ve decided I want to use a different publishing name. Do I have to buy new ISBNs?
No. You can add the new name as an imprint of your original publishing name. If you let Nielsen know the new name, they’ll add it to your account so next time you register a book, you’ll be given a choice of which name you want to use. However, you can’t change the name of the publisher for books you’ve already publishing. The only way to do this is to publish a new edition with a new ISBN under the new imprint.